Scan results different on different TV's?

I was having trouble with my old OTA TV antenna the other day, a Clearstream 2MAX. Did a lot of scans on it upstairs where the Tablo is, as I tried different positions for the antenna. When I’d settle on a position for the antenna, I’d go downstairs and scan using that TV as a sanity check, and get different scan results. Finally decided to replace the Clearstream 2MAX with a Clearstream 4MAX, after 5 good years with the Clearstream 2MAX. FIxed my recent problems, all 36 channels that I get are now 5 green dots, but the scan results still differ. The downstairs TV finds more channels than the upstairs TV.

This is odd, since the channel scan results really shouldn’t depend on the TV, it’s the Tablo scanning what it sees from the OTA antenna. How can the scan results differ on different TV’s? This isn’t earthshaking or a showstopper, we get plenty of channels, but it is bothering me from a scientific point of view. If the scan is between the Tablo and the OTA antenna, how can this be?

Any ideas? Maybe the problem is that I’m scanning channels on two different TV’s :-)? Both are 6-year old Samsung 4K UHD TV’s that work really well. This just doesn’t make sense to me.

The quality of the tuner is different on different TVs (and the Tablo). Some do better with weaker signals, some are better at filtering our multi-path interference, and so on.

Your right, the TV should have nothing to do with the Tablo scan feature.
The location of the antenna, and any obstructions would affect scan results.

Scanning from upstairs TV is worse… is the antenna inside, or outside the house?
My mom’s antenna is the same kind mounted on my roof, but her’s is inside a bedroom on the 2nd floor.
Most of her channels are being broadcast thru anyone inside that bedroom, the hallway, and another bedroom.

Hmm…I thought that the Tablo was the tuner being used here. Not using the tuner in my TV, that’s for sure.

Just can’t make sense of it. I suppose that the tuners in the Tablo might have different sensitivities, but that doesn’t make sense to me, either. If I designed tuner chips, I’d like them to all be the same.

I suppose that it might be an artifact of how the Tablo splits the OTA antenna signal between the tuners. I know that outputs from the same splitter usually have different signal levels. Yeah, that must be it, got it.

The antenna is indoors, closer to the upstairs TV. Which is the TV that gets less stations on the scan.

Thinking that the way that the OTA antenna signal is split by the Tablo between the tuners might be the source of this.

I could verify this (maybe) by bringing our third TV into play, and work on shifting the tuners around to different TV’s. To see if the “better scan” shifts with it. Or just turn both TV’s off, and turn on the downstairs one first…I assume that tuner allocation is first come, first serve not some kind of hashing that would insure that the same TV gets the same tuner…but who knows?

The TV tuner is not being used for Tablo scanning.
To be clear, the Tablo tuner has multiple variables during a scan: line of sight to broadcast towers, broadcast tower equipment power changes, weather, temporary obstructions (birds, people, …).
The signal strength, and quality will not be exactly the same from moment to moment.
It should be close, but never guaranteed.
Usually, this doesn’t matter for most good signal strength channels.
However, there will be times when a good signal strength channel just won’t come in properly, like a couple of mine several months each year, and even several hours per day.

Your physical body is probably blocking the OTA signal. :slight_smile:
To verify this, have someone physically be where you usually are when performing the scan from upstairs bedroom, while you are downstairs performing the scan using the TV down there.
Bet the scan results will look the same as when you do it from upstairs.

You’re suggesting you are scanning channels via your TV. While I believe you’re scanning channels on your tablo with some device/app while watching the progress on 2 different TVs ??

Are you comparing the channel scans from your tablo to the scans you get to your 2 TVs? (as many seem to follow)?

Are you using the same device to access your tablo from each TV to engage your scan?

I like your theory, but the antenna is over my head, about 8’ off the floor and a few feet away in the bedroom where the Tablo is. Admittedly RF is a black art, but I’d be surprised to find that there was any interaction with my body and the antenna. At least enough of an interaction to explain the scan differences that I saw.

If I did the experiment, I suppose that the person that I used would have to be the same height and weight, and dressed the same (metallic belt buckle and metallic buttons on my shirt, not to mention the change in my pocket and pocket knife :-).

No use of the TV tuners was meant to be implied. All channel scanning was done using our single 4-tuner Tablo. I have an Apple TV box both upstairs and down. Both Apple TV boxes are connected to my network via wifi-6.

So, hard to explain, and in my mind has to come down to something happening in the Tablo, Since the scans are between the Tablo tuners and the OTA antenna, external factors shouldn’t come into play (other than the bodily interaction theory, of course).

The human head is the most important part to match.
My fat head in front of an OTA antenna will block way more signal than my wife’s. :slight_smile:

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Yea, screwy. But “something in the Tablo” – nothing changes here, so it’s unclear what’s “in” the tablo causing any fluctuation.

You have an inside antenna? (not an ideal location) It theorized you physically location to the antenna has significant impact on it’s reception? (imo, lame antenna).

When you change floors do you turn off/on any electrical device? including lights. There have been mysterious reports some of the most obscure things things causing reception issues. The kind of “I wouldn’t have believed it, if I weren’t there” bizarre events.

One suggestion, stop repetitive scans. Leave well enough alone.

Did the scans during the day, no lights needed upstairs or down. And yes, I’m not doing any more scans for a while…the new antenna has settled things down to the “don’t have to think about it” level.

Keep in mind that the Tablo has a splitter of some sort to split the OTA antenna signal between the tuners. That could be biasing things. Don’t know enough about what’s inside a Tablo to be able to suggest another Tablo-based reason for this, or even whether the way that the Tablo splits the OTA signal could be the cause, but I feel that it is Tablo-based. While I’m aware that RF is mysterious, we’re not talking difficulties, or even issues here, just differences. It might be that my downstairs TV is haunted, too, but I’m putting that into a lower category of possibility.

Anyways, I feel lucky that I don’t have to care. Unexplained events do bother me, though :-). Made me a better computer programmer when I was working.>

The main difference between the Tablo and a traditional TV is that the Tablo has multiple tuners - so that you can watch and record multiple shows at once.

The drawback here is a small loss in DB when the signal is split. We use amplified splitting technology to mitigate for this loss, so it’s nearly negligible. In some rare cases, you could have one channel on your TV that doesn’t appear on the Tablo.

My antique antenna is outside, up ~25’ with an amp-splitter one run is split between 2 TVs and a Tablo Quad. The other is a 50’ run to another TV and a Tablo Dual Lite. I’ve 40-60 miles from any transmitting tower. Even when my cat would lay on my tablo Tablet too hot and - #11 by djk44883 it made no impact on it performance.

If you have a good quality signal, a split here or there shouldn’t drop it enough to loose the channel from what I can tell. There are a lot of fear-mongering about splitting though.

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I been antenna mostly 20+ years since buying this house. Indoor antennas can be picky or they can be fine. I would always go outdoors and as high up as you can, but I know many can’t do that. Sounds like your going in the right direction by moving it around to where is best. You can try adding an adjustable gain splitter and see what happens. Buy off Amazon as they have easy returns.

Also why are you doing channel scans at every TV? You usually only have to do it 1 time and then just use the Tablo on the other other TV’s. You need to be careful doing to many scans around the same time, as on occasion the Tablo will mess up the saved channels, double them and things like that. I had that issue before I would not get my channel list correct, I forgot the fix, think I emailed them.

Run the scan 1 time where you think you get the most channels and just go with that. This has nothing to do with the Tablo tuners, it is the antenna signal.